The present invention is broadly directed to surgical instruments, and more specifically to instruments useful in arthroscopic surgery and similar surgical procedures wherein access to the surgical site is limited and/or difficult.
The surgical environment of the invention normally involves performance of surgical procedures through small incisions through which the instruments are introduced and subsequently manipulated. With the use of surgical cutting instruments, for example cutting blades, substantial care must be taken not only in the cutting manipulation thereof, but also in the actual introduction of the cutting blade to the cutting site and the subsequent removal therefrom.
As noted in substantial detail in Aikins, U.S. Pat. No. 4,491,132, issued Jan. 1, 1985, one known procedure for the atraumatic introduction of a cutting instrument utilizes a protective sheath. The sheath, a linear hollow member, has the blade completely received and sheathed therein. The blade remains in the sheath until the distal or forward end of the sheath is positioned proximate the site of use. At that time, the blade is mechanically extended from the sheath, either by an actual extension of the blade from the sheath or by a corresponding retraction of the sheath relative to the blade. The Aikins patent notes the desirability for such instruments and discloses selected variations thereof.
The necessity for surgical procedures in limited access environments has also led to the development of instruments incorporating means for guiding a cutting blade or the like during the actual use thereof at the cutting site. Such known means include opposed guides or tracks along which the blade travels during the cutting operation. In this regard, note the following:
Roberts et al; U.S. Pat. No. 3,835,859; Sept. 1, 1974 PA0 Le Noir; U.S. Pat. No. 4,067,340; Jan. 10, 1978
The instrument in Roberts et al is limited in its use in that the guided nature of the blade enables use of the blade only for a removal or slicing of material from a surface. It cannot be used to make a perpendicular cut. Further, the instrument itself is rather cumbersome, requiring the use of two handles to adjust the wire shape and position, after which the blade has to be moved forward in a separate motion.
The Le Noir instrument has been devised for a specific procedure, and is not readily adaptable for general cutting purposes in either arthroscopic surgery or other surgery. Further, the tool itself is rather cumbersome and utilizes two insertions to position and align the opposed guide grooves to carry the flexible blade therebetween.